From Rabbi Kaplan's Handbook Of Jewish Thought, chapter 2, paragraph 3.

As creator of the universe, God's existence can't depend on any of His handiwork. Judaism therefore rejects any definition of God as an abstract ethical force or social convention.

In footnote #2 he writes: "Thus, God cannot be defined as love, truth, justice, goodness, or in any other other human terms. While these are attributes of God, they are not God Himself".